Start making those phone calls at random times. Start skipping a weekend here and there. In some families, having set times of the week or month to call becomes a custom that all enjoy. That is not your case. Good for you in figuring out that the weekend calls have become a control tool. Start skipping occasionally. Once in a while, go more than a week without calling. Then ignore the texts that this prompts. Then call at a time of your own choosing. Avoid explaining yourself to you parents. Making you feel you have to do that is just more controlling. Just say, "I'll keep in touch, but I can promise exactly when I will call, but I'll get back to you."

They are going to get worse, as they get older and find they really do need you. Then, only you can decide how involved you want to be. That 200 miles distance is a real good thing to have. Your going to have to accept that being your own person is going to upset them. They'll get over it.